Electrical relay



Patented Oct. 25, I932 UNITED STATES PATENT OFFICE PAUL IP. SOSINSKI, OF SWISSVALE, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA ELECTRICAL RELAY Application filed July 23,

without affecting the adjustmentofthe armature or other elements associated with the magnet.

I will describe one form of electrical relay embodying my invention, and will then point out the novel features thereof in claims.

In'the accompanying drawing, Fig. 1 is a vertical longitudinal sectional view showing one form of electrical relay embodying my invention. Fig. 2 is a vertical sectional view looking into the front of the relay, with a portion of the cover removed and contact fingers not shown for simplicity. Fig. 3 is an enlarged sectional view of a portion of the magnetic circuit of the relay showing in detailvthe' mechanism for varying the reluctance of the magnetic circuit.

Referring to the drawing, the relay comprises a top-plate A of non magnetizable material inwhich are moulded two magnetizable pole pieces B and an armature supporting bracket (1 of non-magnetizable material. A magnetizable armature D, bridging the pole faces of pole pieces B is pivotally supported in bracket C by a pin E and carries contact fingers F which cooperate with front contact posts G and back contact posts H.

Magnetic flux is supplied to pole pieces B by a winding K mounted on a magnetizable backstrap L which is fastened across the pole I pieces B by means of two adjustable screws M. A glass cover P fastened to the top-plate A encloses the operating elements of the relay. When winding K is energized, the armature D is attracted toward the pole pieces B, thereby moving fingers F into engagement with contacts G. When winding K is deenergized, armature D drops away from the pole pieces B and allows fingers F to en gage back contacts H.

Under certain conditions, it is desirable to vary the value of current at which the relay will pick up and release. To accomplish this result, I have provided a means for adjustment shown in detail in Fig. 3 which permits the position of the backstrap L to be varied 1931. Serial N0. 552,629.

with respect tothe pole pieces B, thereby varying the length of the air gap between these members. The resulting variation in the reluctance of the magnetic circuit, supplied with fiux by the winding K, provides a means for varying the current required in winding K to pick up the armature D. Each pole piece B and each end of backstrap L is provided with arecess R in which is placed a compression spring S of non-magnetizable material which urges the backstrap L upwardly away from the pole pieces B. The

screws M serve to clamp the backstrap L to pole pieces B and, when rotated, allow the air gap between these members to be varied. It should be particularly noted that I have provided the screws M with a magnetizable upper portion M and a non-magnetizable lower portion M which portions are joined together in any suitable manner at Q.

I have found that in the application of this type of relay to railway signaling, it is highly desirable that it should be possible to make the pick-up adjustment in very small increments in order that sensitive response of the relay will result in service. When the adjusting screw M is made wholly of non-magnetizable material, the pick-up adjustment curve is very steep in the neighborhood of zero air gap between backstrap L and pole pieces B; that is, a small rotational movement of a screw such as M, even thoughhaving a fine pitch thread, results in a. large change in pick-up. Since adjustments in the neighborhood of zero air gap are those most used in service because of the greater operating eiiiciency of the relay under these conditions, it is desirable that the pick-up curve be very gradual during the initial movement of screw M. By making the upper portion M of screw M of magnetizable material, a path of low reluctance is provided from back strap L to pole pieces B, which decreases the effectiveness of the air gap during the first few turns of the screw, resulting in a very gradual change in pick-up. When the air gap becomes appreciable, due to continued rotation of the screw, the pick-up changes more slowly per unit of movement of screw M, and the lower non-magnetizable portion ture or contacts.

M of the screw becomes effective in cutting off the fiux path through the screw. Therefore, the full range of adjustment, substantially equivalent to that obtainable with a wholly non-magnetizable screw, can be obtained when the screw M is backed out to the limit of its movement,

One advantage possessed by relays constructed in accordance with my invention is that the operatingcharacteristics of such relays can be adjusted without the necessity for disturbing the adjustment of the more delicate elements of the relay such as the arma- Another advantage is that the operating characteristics can be adjusted very gradually per unit of movement of the adjusting member throughout the full range of the adjustmentwhich is provided.

Although I have herein shown and de-. scribed only one form of electrical relay embodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appended-claims without departing from the spirit and scope of my invention.

Having thus described my invention, what Iclaim is:

1. In combination, a magnetic structure comprising two fixed magnetizable pole pieces terminating in spaced pole faces and a movable magnetizable core bridging the free ends of the pole pieces, a movable armature arranged to be attracted by said pole pieces, means for constantly urging said core away from said pole pieces, and'adjustable-clamping means including a member having a first magnetizable portion and a second non-magnetizable portion for drawing said core toward said pole piecesagainst the bias of said means whereby said first magnetizable portion is eliective in providing a. flux pathfrom said core to one of said polepieces during apart only of the total movement of which said'adjustable clamping means is capable.

2: In combination, a magnetic structure comprising two fixed magnetizable pole pieces terminating in spaced pole faces and a movable magnetizable core bridging the free ends of the pole pieces, a movable armature arranged to be attracted by said pole pieces, means for constantly urging said core away from said pole pieces, and an adjustable clamping screw comprising a first magnetiz- "able portion and a second non-magnetizable portion for drawing the core toward the pole pieces against the bias of said means.

3. In combination, a magnetic structure comprising two fixed magnetizable pole pieces terminating in spaced pole faces, a

movable armature arranged to be attracted by said pole pieces, a single electromagnet having a magnetizable core passmg therethrough and bridging the free ends of the =pole pieces, means for constantly urging said flux path from said core to one of said pole pieces during a part only of the. total movement of which said adjustable clamping means is capable.

"I. In combination, a magnetic structure comprisin g two fixed magnetizable pole pieces terminatin in spaced pole faces, a movable armature arranged to be attracted by said pole pieces, a single electroma'gnet having a magnetizable core passing therethrough and bridging the free end ofthe pole pieces,

means for constantly urging said core and magnet as a whole away from the pole pieces, and an ad ustable clamping screw comprising a first magnetizable portion and a second non-magnetizable portion for drawing the core and magnet as a whole toward the pole pieces against the blas of said means.

5. In combination, a magnetic structure comprising two fixed magnetizable pole pieces termlnatingin spaced pole faces, a, movable armature arranged to be attracted by said pole pieces, a single electromagnet.

having a magnetizable corepassing therethroughand bridging the free ends of the pole pieces, means for constantly urging said core and'magnet as a whole away from the pole pieces, and an adjustable clamping means for drawing the core and magnet as a whole towardthe pole pieces against the bias of said means, and means associatedwith said clamping meansefiective in providing. a flux: path from said core to one ofsaid pole].

pieces during a part only of the total moves ment of which said. adjustable clamping means is capable.

6. In combination, a magnetic structure comprising two fixed. magnetizable pole pieces terminating in spaced pole faces and amovable magnetizable core bridging the free ends of the-pole pieces,a movable arma ture arranged to be attracted by said polo pieces, means for constantly urgingsaidcore away from said pole pieces, adjustable clamping means for drawing saidcore toward thepole pieces against the bias of said means, and means associatedwith said adustable clamping means effective in providmg a flux path from said core tonne of said pole pieces during a part only of the total movement of which said adjustable clamping means is capable.

In testimony whereof I afiix my signature.

7 PAUL P. SOSINSKI. 

